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VGA (Variable Gain Amplifier)
AGC (Automatic Gain Controller)

VGA + level detector + feedback loop = AGC

Ex:
AGC will give a fixed amplitue output, but VGA only give gain.
So uasualy, VGA is a part of AGC.
For example VGA gain is form 10dB to 70dB.


if you want a -20dB output, but he input is -70dB.
So the gain will be 50dB auto contralled by AGC.

the AGC loop is a feedback loop , which make the output ampliftude is always constant as the input chanege so it employ a VGA

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※ 作者: uefangsmith 時間: 2014-01-17 20:08:28